The present invention relates to a device and method for isolating a vibration source from its environment.
Homeostatic systems, such as the system disclosed in U.S. Pat. No. 4,946,128 to Cunningham, have been used to absorb shocks resulting from application of external forces to the systems. In these systems, an elastic member capable of bending to assume a more or less bowed position in proportion to the magnitude of a load applied to its midportion, is supported at a distance from its ends on a fixed bearing support. The ends of the elastic member slide in channels, grooves or sleeves relative to the points of support as the force applied to the member varies and the elastic member bends in response to this applied force. The channels, grooves or sleeves are made of friction-producing materials such that energy added to the system by the applied force may be dissipated as heat. Such systems are capable of providing shock absorbing functions only when the elastic member engages the bearing support at an angle within a critical range and the energy added to the system by the shock(s) is dissipated outside the system.
These systems, however, are not suited for use in isolating a vibration source from its environment because the frictional engagement of the elastic members by the bearing surfaces, which is required to performance of the shock absorbing function, may transfer vibration from the loaded elastic member to a bearing support. The critical angle limitations present in shock absorbing systems also unduly limit vibration isolation systems. In addition, the heat buildup associated with the frictional energy dissipation of homeostatic shock-absorbing systems may be undesirable in some vibration isolation applications.
A need exists for a device that is capable of isolating a vibration source from its environment, and that is capable of operating under a wide range of vibration frequencies and amplitudes.
It is an object of the present invention to provide an apparatus and method for isolating a vibration source from its environment.
It is another object of the invention to provide an apparatus and method that is capable of isolating vibration over a wide range of frequencies and amplitudes, including but not limited to vibration frequencies as low as one hertz (Hz) or less, and particularly an apparatus that may be tuned to effectively respond to a particular source vibration frequency.
It is a further object of the invention to provide an apparatus and method that is capable of minimizing the energy that is lost by the apparatus and its vibration source, and that does not generate appreciable amounts of heat.
It is yet another object of this invention to provide an apparatus and method for isolating a vibration source from its environment in which the vibration source is placed in communication with an elastic member that engages its bearing supports in an essentially frictionless manner over a wide range of engagement angles.
The foregoing objectives are achieved in an apparatus and method that isolate a vibration source from its environment and are effective over a wide range of vibration frequencies and amplitudes. The present invention accomplishes these objectives by minimizing the energy that is lost by the apparatus and its vibration source, such that the apparatus and method do not generate appreciable amounts of heat. The present invention includes a bearing support and an elastic member that may be placed in communication with a vibration source. The elastic member is capable of bending from an original position to assume a more or less bowed position in response to changes in a load applied to the midportion of the elastic member intermediate its ends and returning essentially to its original position when the original load is restored. The elastic member engages a friction-resistant surface on the bearing support at a distance spaced from each of its ends, and moves relative to the bearing surface in response to a bending of the elastic member. The effectiveness of the vibration isolation increases as the friction between the elastic member and the bearing surface decreases, preventing the transfer of energy from the vibration source to the bearing support through the elastic member. The apparatus may be tuned to effectively respond to a particular source vibration frequency, for example, by altering the properties of the elastic member or by changing the distance between the points on the bearing support that engage the elastic member.
These and further objects of the invention will become apparent from the following detailed description.